This invention relates to a mounting for machinery.
It is conventional in some areas of marine engineering to mount machines, including an engine, on a raft which is then installed in the hull of the ship with the inter-position of springs and shock absorbers as a means of reducing the amount of noise transmitted through the hull.
Hitherto, the raft has been made as rigid as possible. This has resulted in a very large and heavy structure. Even so, however, problems are sometimes experienced as a result of vibration and flexing of the raft. This results in undesirable noise and can also result in breakdowns because of imperfect alignment of different articles of the machinery. One example of such problems has been the fracture of fuel pipes.
In U.K. patent application No. 2119897A, a means of damping or eleminating vibrations from a single point source is disclosed using a very simple active vibration control system.
The sensor detects a displacement due to vibration and controls a related actuator to oppose the vibration. Three such pairs of devices operating in the three mutually perpendicular axes will cancel the vibration in all directions. This is a basic idea of active vibration control but does not address the above problem.
The object of this invention is to solve the above problems.